Adoption and crop productivity impacts of sustainable agricultural and land management practices in Zambia

Abstract:

Agricultural productivity in the Sub Saharan African (SSA) region has been cited to be low (Suttie & Benfica, 2016). As a result, there is a consistent call for evolution in smallholder farming. In addition to improving agricultural productivity, this evolution should factor in adaptation to climate variability and change. To achieve this, the use of sound and sustainable agricultural and land management practices (SALMPs) stands paramount. Among these include: (1) improved agronomic practices such as the use of improved seed varieties (HYV), (2) integrated nutrient management practices (INM), (3) tillage and residue management practices (TRM), (4) water management practices (WM), and (5) agroforestry practices (AF) (Branca et al., 2011 and Smith et al., 2007). These sets of SALMPs have been argued to be more environmentally friendly and are associated with positive and significant productivity impacts, in isolation and/or combination.
Even though several studies that analyse adoption and impacts of various agricultural practices exist, they are limited to single practices mostly. However, it is seldom that farmers adopt agricultural practices in isolation. Consequently, factors influencing adoption and impact of individual and combined sets of agricultural practices remain elusive. For instance, the influence of location specific and weather covariates with potentially significant effects on adoption decisions have not extensively been investigated. Among these variables include: agro-ecological zones and weather factors — temperature and rainfall. To address this issue, this study includes dummies for the three agro-ecological zones (AEZs) in Zambia and actual historical temperature and rainfall data as explanatory variables. This is a step farther as opposed to using indicative variables based on farmer perceptions. Crop productivity, gross value of production and net revenue impacts of individual and combined sets of SALMPs are also estimated to achieve the main objective of the study. Unlike most studies, this research project uses panel data. A second panel sample is created for first-time adopters primarily to estimate pure adoption impacts of individual and combined sets of SALMPs.
The study findings show wide-spread distribution of SALMPs adoption sets by AEZs. The widely practiced sets of non-mutually exclusive SALMPs were HYV, TRM and INM practices, whereas AF practices were the least adopted. At household level, extensively practiced sets of SALMPs in combination include: HYV and INM practices, and HYV, INM and TRM practices. Various human and social capital characteristics, wealth status of the household, resource constraint and access to information variables, location and field level characteristics are found to have significant effects on adoption decisions. More interestingly, the influence of agro-ecological zone location dummies and weather factors are mixed. For example, compared to AEZ I a drier zone with the poorest distribution of rainfall, farm households located in AEZ IIa (area with good agricultural potential are significantly less likely to adopt WM practices). Also, higher average temperatures significantly lower the likelihood of adopting most sets of SALMPs, whereas adoption and dis-adoption is more likely with increase in the average rainfall during the growing season. This to some extent, indicates the climate variability and change adaptability potential of several SALMPs.
Lastly, the results from the impact analysis show that combining different sets of SALMPs yields positive and significant crop productivity gains per hectare. On average, the gains in crop productivity for widely practiced sets of SALMPs — HYV, INM and TRM practices and HYV and INM practices, are above 15 percent. This shows that greater productivity gains can be realized by adopting various combinations of different individual sets of SALMPs. In fact, first-time adopters were found to be better-off when specific sets of SALMPs are adopted in bundles. However, the expected net revenue impacts of individual and combined sets of SALMPs are mixed, even though they are negative for the most part.
These study findings support the positive and significant crop productivity impacts of SALMPs. However, the negative net revenue impacts, among maize selling households, suggest that the gains in crop productivity may not be sufficiently large enough to offset variable production costs. This, therefore, calls for simultaneous promotion of agricultural technology uptake and maize commercialization through value addition.